A converter steelmaking method with high stability

Abstract

The application discloses a converter steelmaking method with high stability, which comprises the following steps: charging, oxygen supply adjustment, temperature adjustment and the like. Through the method, the converter steelmaking method with high stability is realized. In the converter blowing process, a reasonable gun position is controlled, less or no iron ore is added, and the lime and dolomite adding amount is increased, so that a small dry and a method for reducing FeO in the consumption slag are manufactured. The method solves the problem that splashing is prone to occur in the process of smelting low-Si molten iron in the converter, the furnace condition is unstable, and the final composition is affected. Under the premise that the existing production equipment is not changed, the effect of stabilizing the converter condition is achieved, the erosion of the furnace lining caused by splashing is reduced, the service life of the furnace lining is improved, the smelting cost is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of steelmaking technology, and in particular to a converter steelmaking method with high stability. Background Technology

[0002] For many years, during the smelting process in a top-and-bottom blown converter, low-Si molten iron is prone to violent splashing due to improper operation, which can damage the furnace lining, affect the stability of smelting, and have a significant impact on the final steel composition. Therefore, improvements are needed. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0004] A converter steelmaking method with high stability is provided, the steps of which include:

[0005] S1. Loading: Raw materials are added in a quantitative manner. Each batch of raw materials includes molten iron, light scrap steel, and heavy scrap steel, and the weight ratio of molten iron, light scrap steel, and heavy scrap steel is 12-13: 1-1.5: 1-1.5.

[0006] By adopting quantitative loading, the equipment's maximum potential is effectively utilized, production organization and processes are stable, and it is beneficial for workers' operation.

[0007] S2. Oxygen supply regulation: Adjust the position of the oxygen lance in real time according to the current temperature of the molten pool so that the output port of the oxygen lance is 1500-2200mm away from the molten metal surface, so as to blow oxygen into the furnace.

[0008] The control of the oxygen lance position plays a decisive role in the temperature change of the molten pool. By flexibly adjusting the lance position, the temperature and slag formation during the converter smelting process can be well controlled. When operating at a low lance position, oxygen, molten slag, and molten metal are in close contact in the molten pool, resulting in a faster chemical reaction rate in the furnace, which also accelerates the temperature rise of the molten pool and strengthens the stirring speed. When operating at a high lance position, the chemical reaction rate in the furnace is slower. Improper control can increase the mass fraction of FeO in the slag, easily causing splashing and increasing heat loss.

[0009] Because the amount of limestone, dolomite, and iron ore added is relatively large, slag is easily formed and has good flow properties. Therefore, the oxygen lance position (H / mm) of this invention is controlled to be 1500~2200mm away from the metal liquid surface.

[0010] S3. Slag Formation: Slag-forming materials are added to the furnace using a single-slag operation method. The composition and weight ratio of the slag-forming materials are: dolomite 28-42: lime 25-28: magnesium balls 5-6: iron ore 23-40.

[0011] The slag from an oxygen converter steelmaking furnace can be simplified into a ternary system of CaO-SiO2-FeO. The slag materials include lime, dolomite, magnesia granules, and iron ore. Half of the total slag material is added during the initial blowing process, with the remainder added in multiple batches. A slag sampling device is used to monitor the FeO content in the slag in real time, ensuring that its content remains within a preset range (e.g., around 16%) to maintain a slightly dry state. No fluxing agents such as fluorite are required throughout the blowing process.

[0012] S4. Temperature regulation: Real-time acquisition and monitoring of furnace temperature to ensure an initial temperature of 1312-1365℃ and an end temperature of 1650-1670℃;

[0013] The cooling effects (physical and chemical cooling) of limestone, dolomite, magnesium spheres, and iron ore can effectively control furnace temperature. For low-Si molten iron, which heats up rapidly, the excess heat generated during smelting can be balanced by increasing the amount of these materials added, and the final tapping temperature can be determined based on the casting temperature.

[0014] S5. Real-time monitoring of oxygen consumption, oxygen blowing time, elemental composition and content in the furnace. When the oxygen consumption meets the preset oxygen consumption threshold, the oxygen blowing time meets the preset time threshold, and the elemental composition and content meet the preset requirements, prepare to tap the steel.

[0015] In a preferred embodiment of the present invention, in S1, the raw materials include 120t of molten iron, 10t of light scrap steel, and 10t of heavy scrap steel.

[0016] In a preferred embodiment of the present invention, in S5, the elements detected in real time include carbon, phosphorus and sulfur.

[0017] In a preferred embodiment of the present invention, at the end of steelmaking, the percentage of chemical elements includes: C=0.02~0.2%, Mn=0.67~1.7%, Si=0.25~0.6%, S=0~0.04%, P≤0.02%, and the remainder is Fe and trace elements.

[0018] The beneficial effects of this invention are as follows: During the converter blowing process, by controlling the reasonable lance position, adding less or no iron ore, and increasing the amount of lime and dolomite added to create a small dry slag and consume FeO in the slag, the problem of easy splashing during the smelting of low-Si molten iron in the converter, which causes unstable furnace conditions and thus affects the final composition, is solved. Without changing the existing production equipment conditions, the converter furnace conditions are stabilized, the erosion of the furnace lining caused by splashing is reduced, and the furnace lining life is improved. This not only reduces smelting costs but also improves production efficiency. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. This patent was supported by the Jiangsu Higher Education Institutions' "Blue Project" (2025).

[0020] The embodiments of the present invention include:

[0021] Example 1

[0022] A converter steelmaking method with high stability includes the following steps:

[0023] Loading system: Quantitative addition is adopted, with 120t of molten iron, 10t of light scrap steel, and 10t of heavy scrap steel.

[0024] Oxygen supply system: Oxygen lance position (H / mm), 1500~2200mm from the metal liquid surface.

[0025] Slag-making process: Single slag operation is adopted, with 6200 kg of dolomite, 4100 kg of dolomite, 3400 kg of iron ore, and 800 kg of magnesium spheres.

[0026] Temperature regime: The steel grade being smelted is Q345, the initial molten iron temperature is 1312℃, and the final temperature is 1653.36℃.

[0027] Iron composition system: The mass percentage of the final chemical composition of carbon, manganese, phosphorus, sulfur, etc. is shown in Table 1.

[0028] Table 1 Chemical composition of molten iron in Example 1 (%)

[0029] Element C（％） Si (%) Mn (%) P（％） S（％） Detection value 4.54 0.37 0.5 0.1 0.016

[0030] Endpoint system: The mass percentage of the endpoint chemical composition, such as carbon, manganese, phosphorus, and sulfur, is shown in Table 2.

[0031] Table 2. Endpoint chemical composition (%) of Example 1

[0032] Element C（%） Si (%) Mn (%) P（%） S（%） Check value 0.147 0.291 1.304 0.015 0.014

[0033] Example 2

[0034] A converter steelmaking method, comprising the following steps:

[0035] Loading system: Quantitative addition is adopted, with 120t of molten iron, 10t of light scrap steel, and 10t of heavy scrap steel.

[0036] Oxygen supply system: Oxygen lance position (H / mm), 1500~2200mm from the metal liquid surface.

[0037] Slag-making process: Single slag operation is adopted, with 5300 kg of dolomite, 4100 kg of dolomite, 3300 kg of iron ore, and 800 kg of magnesium spheres.

[0038] Temperature regime: The steel grade being smelted is X70, the initial molten iron temperature is 1325℃, and the final temperature is 1661.78℃.

[0039] Iron composition system: The mass percentage of the final chemical composition of carbon, manganese, phosphorus, sulfur, etc. is shown in Table 3.

[0040] Table 3 Chemical composition of molten iron in Example 1 (%)

[0041] C（％） Si (%) Mn (%) P（％） S（％） 4.63 0.51 0.3 0.12 0.015

[0042] Endpoint system: The mass percentage of the endpoint chemical composition, such as carbon, manganese, phosphorus, and sulfur, is shown in Table 4.

[0043] Table 4. Endpoint chemical composition (%) of Example 1

[0044] C（%） Si (%) Mn (%) P（%） S（%） 0.141 0.361 0.79 0.019 0.013

[0045] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A converter steelmaking method with high stability, characterized in that the steps include... include: S1. Loading: Raw materials are added in a quantitative manner. Each batch of raw materials includes molten iron, light scrap steel, and heavy scrap steel, and the weight ratio of molten iron, light scrap steel, and heavy scrap steel is 12-13: 1-1.5: 1-1.

5. S2. Oxygen supply regulation: Adjust the position of the oxygen lance in real time according to the current temperature of the molten pool so that the output port of the oxygen lance is 1500-2200mm away from the molten metal surface, so as to blow oxygen into the furnace. S3. Slag Formation: Slag-forming materials are added to the furnace using a single-slag operation method. The composition and weight ratio of the slag-forming materials are: dolomite 28-42: lime 25-28: magnesium balls 5-6: iron ore 23-40. S4. Temperature regulation: Real-time acquisition and monitoring of furnace temperature to ensure an initial temperature of 1312-1365℃ and an end temperature of 1650-1670℃; S5. Real-time monitoring of oxygen consumption, oxygen blowing time, elemental composition and content in the furnace. When the oxygen consumption meets the preset oxygen consumption threshold, the oxygen blowing time meets the preset time threshold, and the elemental composition and content meet the preset requirements, prepare to tap the steel.

2. The converter steelmaking method with high stability according to claim 1, characterized in that, In S1, the raw materials include 120t of molten iron, 10t of light scrap steel, and 10t of heavy scrap steel.

3. The converter steelmaking method with high stability according to claim 1, characterized in that, In S5, elements detected in real time include carbon, phosphorus, and sulfur. Using a slag sampling device, the FeO content in the slag is detected in real time to ensure that its content in the slag is within a preset range in order to maintain a slightly dry state.

4. The converter steelmaking method with high stability according to claim 1, characterized in that, At the end of steelmaking, the percentages of chemical elements include: C=0.02~0.2%, Mn=0.67~1.7%, Si=0.25~0.6%, S=0~0.04%, P≤0.02%, and the remainder is Fe and trace elements.